package org.apache.commons.graph

import kotlinx.atomicfu.locks.synchronized

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License.  You may obtain a copy of the License at
*
*   http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied.  See the License for the
* specific language governing permissions and limitations
* under the License.
*/

/**
 * A synchronized (thread-safe) [Graph] backed by the specified Graph.
 */
/**
 * Creates a new thread-safe instence of [SynchronizedDirectedGraph].
 * @param g The [Graph] that has to be synchronized
 */
internal class SynchronizedDirectedGraph<V, E>(
    private val directedGraph: DirectedGraph<V, E>
         ) : SynchronizedGraph<V, E>(directedGraph), DirectedGraph<V, E> {

    /**
     * {@inheritDoc}
     */
    override fun getInbound(v: V): Iterable<V> {
        synchronized(this) {
            return directedGraph.getInbound(v)
        }
    }

    /**
     * {@inheritDoc}
     */
    override fun getInDegree(v: V): Int {
        synchronized(this) {
            return directedGraph.getInDegree(v)
        }
    }

    /**
     * {@inheritDoc}
     */
    override fun getOutbound(v: V): Iterable<V> {
        synchronized(this) {
            return directedGraph.getOutbound(v)
        }
    }

    /**
     * {@inheritDoc}
     */
    override fun getOutDegree(v: V): Int {
        synchronized(this) {
            return directedGraph.getOutDegree(v)
        }
    }

    companion object {
        private const val serialVersionUID = 2275587906693672253L
    }
}

fun<V,E> DirectedGraph<V, E>.toSyncGraph(): DirectedGraph<V, E> = SynchronizedDirectedGraph(this)